There is an ever increasing interest in combining field operations to improve economy in crop production, decrease labor, and reduce maintenance on equipment. For example, operations of cultivating and fertilizing could be combined. In fact, fertilizer application can be combined with any of several operations, including seeding, cultivating, weeding, etc. Application of other materials such as herbicides, insecticides, or other treatments may also be properly applied in conjunction with other field operations.
Existing carts have been produced for attachment behind the drawn implement or that may be mounted intermediate the tractor and implement. Existing intermediate carts substantially lengthen the distance between the tractor and implement. This increased length results in poor tracking characteristics of the implement behind the tractor, especially on uneven terrain. Additionally, the tractor may leave tracks on turns that cannot be covered by the trailing implement. A cart mounted between a tractor and towing vehicle will often impede the turning capability of the tractor and attached implement. The implement tongue may pivot into abutment with the intermediate cart wheels on sharp turns. Likewise, the cart wheels can interfere with the tractor on sharp turns. Prior forms of intermediate carts also obstruct visibility of the attached implement from the tractor operator's station.
Known forms of carts mounted between the tractor and implement make use of "crazy wheels" for support. "Crazy wheels" pivot about vertical axes and rotate on horizontal axes. This presents a problem when the cart is moved to a sidehill situation. The weight of the cart shifts on the sidehill, causing the crazy wheels to point downhill. The tendency is thus for the cart to lead the implement downhill. This is a frustrating experience for the farmer who would like the implement to track straight behind his tractor.
Another problem with "crazy wheel" carts is that the "crazy wheels" cannot be used to drive accessories by reason of their free pivotal nature. Expensive and cumbersome drive arrangements must then be provided independently of the "crazy wheels". This involves more than the simple addition of an auxiliary wheel for a direct drive purpose; there must be enough weight distributed over the wheel for driving traction. If there is not enough weight over the wheel, the wheel will seize and skid over the ground from the drag of the drive mechanism. Too much weight on the wheel and the "crazy wheels" become ineffective.
The need therefore remains to effectively combine operations without sacrificing handling characteristics between the tractor and towed implement. It is also desirable to obtain some form of auxiliary material container and applicator arrangement that may be used to interconnect nearly any drawn implement to nearly any form of tractor.